Download 7.2 Cell Membrane

7.2 Cell Membrane
Cell Membrane Function
The Cell Membrane
Section 7.2
Selective Permeability
· a.k.a. semipermeable or
selectively permeable
· only certain substances
can enter or leave cell
· helps maintain homeostasis
b/c cell need very specific
conditions to function
properly
Cell Membrane Structure
· cholesterol - keeps phospholipids from sticking
together
· proteins - help materials cross the membrane
and form part of the cytoskeleton
· carbohydrates - tags for identification
· a.k.a. plasma membrane
· functions
a. maintains integrity of cell (forms a boundary)
like a gate or border
b. controls passage of materials into and out of cell
(selectively permeable)
like a gatekeeper, bouncer, or border control
Cell membrane Structure
· phospholipid bilayer (two layers)
hydrophilic heads (polar) - love water
hydrophobic tails (non polar) - fear water and turn in
FLUID MOSAIC MODEL
· cell membrane is flexible
and moves from side to side
behaves like a liquid
· embedded proteins and
other molecules create
patterns
looks like mosaic tiles
7.2 Cell Membrane
A. phospholipid
A1 - hydrophilic heads
A2 - hydrophobic tails
C, F, G. Proteins
D. Carbohydrates
E. Cholesterol